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Ido connect to the device from my raspberry pi and able to send commands. The power consumption of the SG is 2.5 W. That means that the current of usb port should be 2.5 / 5 = 500 mA.

>>> import usbtmc
>>> instr = usbtmc.Instrument(11120, 66)
>>> instr.ask("*IDN?")
'Micran,PLG12,1105170004,C.4.1'

then i send:

`>>> instr.write("FREQ 10 GHz")
>>> instr.write("POW 10")
>>> instr.write("OUTP 1")

unfortunately i get only 3 dBm output power. If i send the same commands from a PC i do receive 10 dBm as expected also if i send:

>>> instr.cfg
<CONFIGURATION 1: 400 mA>

i connected the Signal generator through a USB hub with a power supply to avoid any power consumption issue but still have the same result. Your help is very appreciated . Thank you!

P.s. picture is added: enter image description here

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Serj
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  • which sg??????? – tlfong01 Jan 08 '20 at 05:07
  • this one? https://raspberrypi.stackexchange.com/questions/104779/how-can-rpi4b-python-uart-talk-to-xy-pwm-signal-generators – tlfong01 Jan 08 '20 at 05:09
  • can use digital signal processor, digital pre amp and digital power amp to amplify to 25W! – tlfong01 Jan 08 '20 at 05:12
  • @tlfong01 Micran,http://micran.com/sites/micran_eng/data/UserFile/pdf/tme/Micran_Portable_Solutions_A5_eng_1%2005_WEB.pdf – Serj Jan 08 '20 at 05:49
  • @tlfong01 it is a standard signal generator that transmits 10dBm on my PC but not on Raspberry pi. – Serj Jan 08 '20 at 05:53
  • Ha, your use of the phrase "standard sig gen" is a bit vague. Me hobbyist's standard sig gen as referred above is 500kHz sine/ square wave. Anyway, let us make it as simple as possible, but not simpler: 500kHz square: Micran Power meter/Power sensor/Frequency synthesizer (USB2.0, 25MHz to 12GHz, -40dBm) http://micran.com/sites/micran_eng/data/UserFile/pdf/tme/Micran_Portable_Solutions_A5_eng_1%2005_WEB.pdf: example: CW LF sig gen 500kHz sine/saw tooth/triangle/square). – tlfong01 Jan 08 '20 at 06:30
  • Before I forgot, (1) Rpi4B USB3 might NOT work with your sigGen which only talks USB2. (2) If it is USB/UART, then you can first use Win10 RealTerm, then python serial to do the testing.(3) If you are using any AT commands, as my cheapie sig gen referred above, give me a link to the user guide and AT command set. Thks and Cheers. – tlfong01 Jan 08 '20 at 06:37
  • And let us first agree on the band and power ranges we are going to mess around: (1) https://imgur.com/gallery/Tk9mHgG. And can you show me any scope screen captures like those in my answer: (2) https://raspberrypi.stackexchange.com/questions/104779/how-can-rpi4b-python-uart-talk-to-xy-pwm-signal-generators?. – tlfong01 Jan 08 '20 at 07:00
  • As shown in my pictures, my cheapy (US$2) sig gen can do 2.5kHz 10dB. How come yours so weak? Are you in the GHz band? – tlfong01 Jan 08 '20 at 07:10
  • @tlfong01 The frequency doesn't meter i get the same power at 25MHz also – Serj Jan 08 '20 at 09:05
  • You might need to use a dual USB cable to provide enough power from the Pi, something like this: https://www.amazon.co.uk/C2G-USB-Mini-b-Male-Y-Cable-Black/dp/B001U3ZP1A/ref=sr_1_11?keywords=usb+split+power&qid=1578474368&sr=8-11 You could then plug the "power" end directly into a USB power supply instead with the "data" end connected to the Pi. Might introduce ground loop problems though... – Roger Jones Jan 08 '20 at 09:10
  • Why should the power supply influence it at all if i use a USB hub with its own power supply in order to avoid any power consumption issues of the Rpi. It's something caused by rasbian configuration. – Serj Jan 08 '20 at 10:16
  • Yes, I am confused by your sig gen. By the way, do you have the USB multi-meter as shown in the picture below. I found it handy to check out USB voltage and current: https://imgur.com/gallery/yymRgEa. – tlfong01 Jan 08 '20 at 14:39
  • And I am using this Ugreen USB3 hub with switchable external 5V 3A wall wart: Ugreen 7-Port USB 3.0 Hub with 12V/4A Power Adapter https://www.ugreen.com/product/UGREEN_USB__Charger_7_Ports_Hub__with_BC_Charging_Station_and_12V_5A_Power_Adapter-en.html. You might use a similar hub to try out things. – tlfong01 Jan 09 '20 at 01:55

1 Answers1

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The issue was resolved by sending *RST command. It seems that the signal generator wakes up in some strange mode (BUG). *RST fix it.

Serj
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